US3466811A

US3466811A - Top supported coolant hood

Info

Publication number: US3466811A
Application number: US590396A
Authority: US
Inventors: Jack M Suddarth
Original assignee: Coburn Manufacturing Co Inc
Current assignee: Coburn Manufacturing Co Inc
Priority date: 1966-10-28
Filing date: 1966-10-28
Publication date: 1969-09-16
Anticipated expiration: 1986-09-16
Also published as: DE1652018A1; DE1652018B2; BE705795A; GB1172398A; DE1652018C3

Description

Sept. 16, 1969 v J. M. SUDDARTH 3,466,311

TOP SUPPOBTED COOLANT HOOD Filed Oct. 28. 1966 M X INVEN TOR F/6.4I BYFWM/ A T TORNFYS '1 JACK M. SUDDARTH United States Patent 3,466,811 TOP SUPPORTED COOLANT HOOD Jack M. Suddarth, Muskogee, Okla., assignor to Coburn Manufacturing Company, Inc., Muskogee, Okla., a cororation of Oklahoma P Filed Oct. 28, 1966, Ser. No. 590,396

Int. Cl. B24b 55/02, 55/04 US. Cl 51266 Claims ABSTRACT OF THE DISCLOSURE This invention generally relates to a cover for a grinding chamber wherein coolant fluids are used and more specifically relates to a movable cover supported at its top and having a positive seal throughout its movement. Because of the large amount of coolant fluids used, the cover finds particular utility in apparatus for grinding ophthalmic lenses.

Prior art covers have displayed several disadvantages. For the most part they have been bottom supported and movable on tracks which become clogged with grinding particles. Additionally, the prior art devices have been lacking in an efiicient positive seal for keepingfurnes developed from the heated coolant from contaminating the atmosphere near the machine operator.

In general, a slotted skirt assembly is rotatably supported from its upper central surface. The bottom edge of the depending skirt fits into an annular lubricating groove in the base pan. In operation, the skirt is locked in place by insertion of a work hold ng chuck through an aperture in the skirt. The sweeping movements of an abrading tool which is inserted through the base pan cause the base pan to rotate about a central vertical axis relative to the aforesaid skirt. The abrading tool will thus move through the slot in the skirt. In order to prevent escape of the fluid generated within the grinding chamber from the slot without increasing the drag on the sweep generator motor, a pair of negators are provided. One end of each negator is secured to the stationary skirt wh le the other end is secured to spools which are moving with the oil pan. n

An important objective of the present invention IS tO overcome the disadvantages of the prior art and provide a movable cover which will not become clogged by grinding particles. l

A further objective of this invention is to provide a movable coolant hood which will eflectively prevent escape of fumes to the atmosphere A yet further objective of this invention is to provide a movable coolant hood having means for maintaining constant rotational bias while simultaneously rolling and unrolling opposite sides of the cover.

These and other objectives of the invention will become more apparent to those skilled in the art by reference to the following detailed description when viewed in light of the accompanying drawings, wherein like elements throughout the figures thereof are indicated by like numerals and wherein:

FIGURE 1 is an exploded view of the cover of this invention;

"ice

FIGURE 2 is a rear elevation view of the upper skirt assembly of FIGURE 1;

FIGURE 3 is a bottom plan view of FIGURE 2; and,

FIGURE 4 is a section taken along line 44 of the upper skirt assembly in FIGURE 1.

In the embodiment described, the cover of this invention is designed for lens grinders of the type which have a work holding chuck which is movable longitudinally into and out of a grinding chamber which houses a rotating abrading tool. Lens grinders of this type incorporate a sweep generator motor for moving the abrading tool through a grinding sweep past the lens blank. Such lens grinders are well known in the art and are described in US. Patent 2,806,327 to O. W. Coburn, dated Sept. 17, 1957, and in copending application Ser. No. 495,827, filed Oct. 14, 1965, by Jack M. Suddarth et a1.

Referring to FIGURE 1, the numeral 10 generally indicates a base member of a grinding chamber while the numeral 12 generally indicates an upper skirt assembly. The base member 10 has a horizontal bottom plate or oil pan 14 one end of which defines a half-circle. Extending vertically upwards from the other end of the oil pan 14 is a support member 16 comprised of a back plate 18, side walls 20 and 2G, and an inwardly directed top bearing surface 22. An aperture 24, large enough to receive a conventional abrading cup is located in the central portion of back plate 18. The inner portions of side walls 2040' are bent inwardly at 26 and 26' respectively. Located at opposite ends of the inner side of the top bearing surface 22 are

semi-circular recesses

28 and 28. A flange 30 extends vertically upward from the periphery of the oil pan 14 and thereby defines a shallow oil coolant retainer chamber 31 with a circular ridge 32 of pan 14 which is spaced inwardly from flange 30. Depending downwardly from the bottom surface of the pan 14 and located centrally of circular ridge 32 is a projection 33. The projection serves to rotatably support the base member 10 on the tool holding assembly of the lens grinder.

A fluid supply housing 34, with attached

nozzles

36 and 38, is secured to the pan 14. The

nozzles

36 and 38 direct a lubricating coolant fluid onto the workpiece during grinding. A conventional supply means to include a reservoir, pump, and supply line leading to the housing 34 can be located without the base member 10. Since it forms no part of the instant invention, it is not shown or described. A passageway or fluid outlet 39 for exhausting the oil and accumulated grinding particles extends from adjacent the inner portion of the ridge 32 down through the pan 14 to a suitably disposed exhaust pipe (not shown). It should be noted that the coolant in pan 14 is maintained at a level corresponding to the height of ridge 32 since it must spill over the ridge prior to reaching exhaust aperture 39.

The top cover 12 is comprised of a circular skirt 40 which is rigidly secured to, and depends downwardly from, the outer periphery of a circular plate 42. A shaft 44 is rigidly secured to the center of the plate 42 and extends vertically upwards therefrom.

The plate 42 and depending skirt 40 are rotatab y supported from above by a support arm 46. The support arm 46 is of triangular shape, and has a circular opening 48 formed at one vertex by arcuate clamping arms 50. The arms 50 closely surround a bearing sleeve 52 and may be adjusted to rigidly clamp the sleeve by means of an adjusting screw 54. The sleeve 52 is rotatably received on the shaft 44. An enlarged supporting rim 56 is formed circumferentially about the upper portion of the shaft 44. The side of the support arm 46 opposite the vertex opening 48 has a downwardly depending flange 58 which is supported on and rigidly secured to the bearing surface 22 by screws 59. The inner side 60 of the flange 58 is spaced from the skirt 40 to allow free relative movement therewith.

Spools 62 and 62' are each located with one of their ends rotatably secured at opposite ends of the flange 58 and depend downwardly therefrom. The exact location of the aforesaid spools is such as to be concentric with the semicircular openings 2828 when the member 58 is secured to the bearing surface 22.

An aperture 64, large enough to freely receive the work holding chuck (not shown), is located centrally of the skirt 40. Resilient sealing flaps 66 extend from the circumference of the aperture 64 inwardly toward its center. The flaps 66 will engage the periphery of the work holding chuck and will keep the work sealed from the atmosphere. A circular ring 70, rigidly secured to the skirt 40 about the circumference of the aperture 64, secures the flaps 66.

A slot 72 extends circumferentially in the skirt 40 from adjacent one side of the aperture 64 continuously to a point adjacent the other side of the aperture 64. The height of the slot 72 is at least as great as the diameter of the aperture 24. As best seen in FIGURE 2, the lower portion of the skirt 40 below the slot 72 and opposite the aperture 64 is removed to leave an opening 73 which is wide enough to permit upward removal of the upper skirt assembly 12 when the abrading tool support arm is inserted.

Two

negator members

74 and 74 are attached to skirt 40 on opposite side of opening 64 to bias the skirt to its central position (FIGURE 1) whereby the opening will always center itself to receive the work chuck. Negators are used so that the bias will be uniform throughout the movement of the skirt. For the sake of convenience and clarity in discussion, only one negator 74 will be discussed, but it is to be remembered that the structure and manner of engagement of negator 74 is symmetrical to negator The negator 74 is an elongated strip of metal which has one end secured to the skirt 40 at a point between the aperture 64 and the end of the slot 72 by a strip '75. The other end of the negator 74 is secured to the rotatable spool 62 and is wrapped therearound in such a manner that, as viewed in FIGURE 3, when it is unrol ing the spool 62 will rotate in a clockwise direction and when rolling up the spool will rotate in a counterclockwise direction. The portion of the negator 74 between the strip 75 and a plane passed through the vertical centerline of the cover 42 and the spool 62 conforms closely to the outer surface of the skirt 40 and seals the sot 72 from the atmosphere. As mentioned above, the negator 74 is symmetrical to the negator 74 and therefore the spool 62 will rotate counter-clockwise when unrolling and clockwise when rolling up. The negator 74 is of suflicient width and length to completely cover that portion of slot 72 which, during normal operation, will extend between the strip 75 and the aforesaid p ane.

Referring to FIGURE 3, if the skirt 40 moves clockwise relative to the support arm 46, the negator 74 will roll up around the spool 62 a specified amount while the negator 74 will unroll from the spool 62' a like amount. The use of negators allows a roll-unrol relationship between spools without changing the bias against further movement in either direction. In other words, there is a constant torque takeup and the bias against torque is the same in any position of the skirt 40.

In the assembled position, the skirt 40 is supported so that its bottom edge projects into the coolant chamber formed by the ridge 32 and skirt 30 but does not contact the pan 14. The aperture 24 is substantially opposite the aperture 64. The pan 14 is maintained with a level of oil which is between the height of the ridge 32 and the height of the skirt 30 and since the bottom edge of the skirt 40 and the bottom edges of the negators 74 and 74' are below this level, the fumes created by the grinding operation cannot escape thereunder. The fumes are also prevented from escaping through the slot 72 because of the sealing relation between the negators 74 and 74' and the skirt 40. The aperture 64 is likewise sealed by the engagement of the flaps 66 and the inserted work holding chuck. The aperture 24 may also be sealed by providing a resilient collar such as rubber or plastic around the abrading cup support arm or by providing similar flaps as in aperture 64.

In operation, the work holding chuck is inserted through the aperture 64 and locked in position. The abrading tool and support arm are inserted through the aperture 24 and when the support arm 46 makes its abrading sweep (assume clockwise in FIGURE 3), it will abut against one side of the aperture 24 and cause the pan 14 and attached support arm 46 to rotate clockwise about the projection 33. The spools 62 and 62' which are rotatably secured to the support arm 46 will thus move clockwise circumferentially. Since the skirt 40 and attached cover 42 cannot rotate because of the fixed chuck in aperture 64, the negators 74 and 74' will unroll and roll up respectively to maintain the slot 72 sealed from the atmosphere. The relative movement between the bottom of the skirt 40 and the pan 14 will not be hindered by an accumulation of ground partic es because the oil resupply line 36 and exhaust 39 will maintain the proper level and quality of oil. The use of negators provides opposed compensators which protect the surrounding area from fumes created by the grinding operation and will not cause any appreciable drag on the sweep generator motor.

What has been set forth above is intended primarily as exemplary to enable those skilled in the art in the practice of the invention and it should therefore be understood that, within the scope of the appended claims, the invention may be practiced in other ways than as specifically described.

What is new and therefore desired to be protected by Letters Patent of the United States is:

1. A housing for enclosing a grinding chamber comprising a generally horizontal oil pan, a vertical flange circumscribing said oil pan, a vertical ridge on said pan spaced inwardly of said flange and defining an annular chamber therewith, said chamber adapted to be filled with oil, a rigid support member extending vertically upwardly from pan, a bearing surface terminating the end of said rigid support member, a support arm aflixed to said support member and having an inner end disposed approximately centrally over said pan member, a top cover rotatably supported at said inner end, a skirt depending from said top cover and having a lower end disposed in said annular chamber immersed in said oil and spaced from the oil pan, said skirt having a slot in its periphery, and means attached to said skirt in sealing relation over said slot for substantially frictionless movement of said skirt in either direction.

2. A housing for enclosing a grinding chamber comprising a generally horizontal oil pan, a vertical flange circumscribing said oil pan, a vertical ridge on said pan spaced inwardly of said flange and defining an annular chamber therewith, said chamber adapted to be filled with oil, a ridge support member extending vertically upwardly from pan, a bearing surface terminating the end of said rigid support member, a support arm afiixed to said support member and having an inner end disposed approximately centrally over said pan member, a top cover rotatably supported at said inner end, a skirt depending from said top cover and having a lower end disposed in said annular chamber and immersed in said oil, said skirt having a slot in its periphery, and .means attached to said skirt in sealing relation over said slot for substantially frictionless movement of said skirt in either direction, said means comprising first and second rotatable takeup spools extending downwardly from said sup port arm, a first biasing member having a first end attached to the circumference of said skirt and a second end affixed to and wrapped about said first spool, and a second biasing member having a first end attached to the circumference of said skirt and a second end affixed to said second spool.

3. The apparatus recited by claim 2 wherein said first and second biasing members provide a uniform bias throughout the rotatable movement of said skirt.

4. A grinding housing in combination with a grinding tool assembly, said housing comprising a top member, support means on said grinding tool assembly for rotatably suspending said top member, a coolant pan disposed below and spaced from said top member, a skirt depending downwardly from said top member and rotatable therewith, said skirt having a length less than the distance between said top member and said pan whereby the lower edge thereof is in spaced relationship with said pan, a plurality of spaced members extending upwardly from said pan and on both sides of the skirt defining a chamber therebetween receiving said lower edge, fluid in said 6 chamber forming a liquid seal between the interior of the housing and the atmosphere.

5. The housing recited in claim 4 wherein said skirt has an elongated opening intermediate its length and a pair of biasing members having first ends respectively attached to either side of said opening and having their other ends attached to said frame.

References Cited UNITED STATES PATENTS 2,589,488 3/1952 Fowler 51-124 2,747,339 5/1956 Schelling 51--124 2,757,487 8/1956 Coburn 51272 X 3,281,006 10/1966 Wei 220-4 JAMES L. JONES, JR., Primary Examiner US. Cl. X.R. 51-268